So I used my preval sprayer for the first time on my cake for my church. It was sprayed on crusted b/c and to review it:
1. you do need to fill the bottle quite full to reach the hose which carriers the paint up to be sprayed.
2. it can sputter until you get the feel of it and adjust your pressure on the sprayer nozzle. So try the lightest spray you can and then adjust.
3. It seems you need to rinse out the hose and the sprayer bottom to get out the left over paint so you deff wanna flush it between uses.
Over all for 5.00 it's not bad. I used it on the sides of my 12x16x3 in double layer cake and was pleased with the effects. With several uses you could probably fine tune it to your desired effects for not very detailed coverage. But to really do the finer details you are just gonna have to bite the bullet and buy a true airbrush system. 
here ia a link to my pic of it. http://www.cakecentral.com/cake-photo_131783.html
For some reason you have to copy and paste it in your browser, it won't just let you click on it. I've tried several times and it keeps doing the same thing.
oh, well. I know it's not the best pic of the sides of cake but I think you can get the general idea of the effect. Thanks for compliments too.
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